PPD-, PWM-, and PHA-induced interferon in stable multiple sclerosis: association with HLA-Dw2 antigen and clinical variables

Diminished production of type-I interferons and interleukin-2 in patients with multiple sclerosis

Several lines of evidence have supported the role of immunological mechanisms in the pathogenesis of multiple sclerosis (MS) and new immunomodulatory strategies for its treatment, e.g. subcutaneous application of interferon (IFN)-beta, have emerged. We investigated the ability of peripheral blood mononuclear cells (PBMC) in 21 consecutive patients with clinically definite MS to produce interferons and lymphokines in response to viral or mitogenic stimulation. Ten patients showed clinical signs of disease activity (acute relapse) and 11 patients were in a stable condition. Additionally, white blood count, leukocyte differentiation and lymphocyte subtyping were performed. A group of age-related healthy blood donors served as control (n=20). There was no difference between patients and controls in the production of IFN-gamma, tumor necrosis factor (TNF)-alpha and soluble interleukin (IL)-2 receptor. IFN-alpha and IFN-beta responsiveness, however, was significantly lower in patients with stable disease than in patients with active disease and controls (p<0.001). Furthermore, secretion of IL-2 after stimulation was significantly diminished in both patient groups as compared to the control group (p<0.01). Analysis of T-cell subsets revealed a significantly lower amount of CD8+ T-cells in patients with stable disease, leading to a significantly higher CD4/CD8 ratio in this group as compared to patients with active disease. Our study depicted an IL-2 deficiency in MS patients which is shared with other autoimmune diseases. In addition, our findings suggest that the ability to produce type-I IFNs, IFN-alpha and IFN-beta, is primarily impaired in MS patients and changes in correlation to the course of disease activity.

Decreased CD3-mediated interferon-gamma production in relapsing-remitting multiple sclerosis

Multiple sclerosis (MS) is a chronic inflammatory disease of the central nervous system that has been postulated to be T-cell mediated. We examined the proliferation and cytokine secretion of mononuclear cells after stimulation with OKT3 (anti-CD3) monoclonal antibody concanavalin A, or ionomycin plus myristic acid palmityl ester in subjects with stable relapsing-remitting MS. Control subjects demonstrated good proliferation to anti-CD3 monoclonal antibody whereas subjects with relapsing-remitting MS showed a significantly decreased anti-CD3 monoclonal antibody-mediated response. There was no difference in concanavalin or ionomycin plus myristic acid palmityl ester stimulation between control subjects and MS subjects. Secretion of interferon-gamma was significantly decreased and transforming growth factor-beta was significantly increased from cultures stimulated with anti-CD3 monoclonal antibody, but not ionomycin plus myristic acid palmityl ester or concanavalin A, in MS patients compared to control subjects. Secretion of interleukin-10 and tumor necrosis factor-alpha was not different between control subjects and MS patients following stimulation with anti-CD3 monoclonal antibody, concanavalin A, or ionomycin plus myristic acid palmityl ester, or of interleukin-2 and interleukin-4 following stimulation with anti-CD3 monoclonal antibody or concanavalin A. An abnormality of signal transduction and secretion of the immunomodulatory molecule interferon-gamma may exist in MS via the CD3 T-cell receptor complex.

Defective CD3 mediated proliferation and LPS responsiveness in multiple sclerosis

Multiple sclerosis [MS] is a chronic inflammatory disease of the central nervous system which has been postulated to be a T cell mediated disease. We examined proliferation of mononuclear cells to OKT3 mAb, Con A, ionomycin plus PMA and human myelin basic protein in subjects with relapsing-remitting and chronic progressive multiple sclerosis. Age and sex matched controls demonstrated a good proliferation to anti-CD3 mAb whereas subjects with relapsing-remitting multiple sclerosis showed a significantly decreased anti-CD3 mAb response. There was no difference in mitogen, ionomycin plus PMA or human MBP proliferation between controls and MS subjects. There was also a trend for decreasing anti-CD3 mAb proliferation in patients with chronic progressive multiple sclerosis compared to controls. LPS significantly decreased anti-CD3 mAb proliferation in controls but not in the MS subjects. An abnormality of signal transduction via the CD3 T-cell receptor complex in T cells and responsiveness to the immunomodulatory effect of IFN inducers may exist in multiple sclerosis.

PHA-induced interferon in multiple sclerosis: association between gamma interferon and clinical and genetical variables

Gamma interferon (INF-gamma) production, after PHA stimulation of peripheral blood mononuclear cells, from multiple sclerosis (MS) patients with the acute remitting and chronic progressive forms, in attack and remission phases, and from normal controls, was studied by immunoradiometric assay. MS patients in all these 4 clinical states of disease produced less INF-gamma (log value range from 2.55 to 2.65). MNC from the total MS patients produced significantly low levels of INF-gamma compared to the control group (log values 2.60 vs. 2.82; P = 0.001). No association between the interferon production and antigens at any HLA locus (A, B, C, Dw and Bf) was found. There was no correlation between IFN-gamma production and age, sex, duration of disease, or disability index. However there was a slight tendency to negative correlation with the progression index of the disease. The results suggest that this lower IFN-gamma production in MS may be secondary to the disease, and the primary defect may be a severe reduction of the essential lymphocyte populations required for an effective lymphokine cascade to produce the normal immune response against infection.

Natural killer (NK) cells in chronic progressive multiple sclerosis patients treated with lymphoblastoid interferon

Natural killer (NK) cell functional activity, as defined by the lysis of 51Cr-labelled K-562 cells, and number, defined phenotypically by anti-Leu-11, are significantly decreased in chronic progressive multiple sclerosis (MS) when compared to normal controls. When age- and sex-matched populations are compared, NK cell functional activity is again significantly reduced in MS compared to controls but not when compared to a control group of other medical disease (OMD). The MS group could be differentiated from the OMD group, however, when results of NK cell functional activity are combined with NK cell phenotype. With the administration of lymphoblastoid interferon daily for 6 months, NK cell activity increased significantly at 48 h and at 1 week. By 1 month, activity decreased to a level slightly above placebo treatment values. The results likely reflect interferon's enhancement of mature NK cell activity combined with a variable effect on recruitment of pre-NK cells.

NK activity and NK-like non-specific cytolysis after PPD, rubella and measles antigen stimulation in multiple sclerosis

Blood samples were collected from 14 pairs of multiple sclerosis (MS) patients and from age- and sex-matched healthy controls. The cytotoxic activity of peripheral blood mononuclear cells was tested against the K562 cell line on the day of collection and again after 3 days in vitro culture with medium or with purified protein derivative of tuberculin (PPD), inactivated rubella virus or inactivated measles virus antigen. Lymphocytes from MS patients had a lower spontaneous cytotoxic activity compared to the controls both on the day of collection (P less than 0.025) and after 3 days in culture with medium alone (P less than 0.025). The activity decreased during in vitro culture in both groups, but the decrease was greater among MS patients (P less than 0.05). In cultures with antigens, a strong increase of NK-like cell-mediated cytolysis (NK-like CMC) was noted especially in cultures stimulated with PPD. There were no significant differences in the increase of the activity among MS patients and control subjects. A significant correlation between the increase of NK-like CMC and the lymphocyte blast transformation response induced by each antigen was found.

Comparison of HLA-Dw1 and -Dw2 positive adherent cells in antigen presentation to heterozygous T-cell lines: a low rubella antigen-specific response associated with HLA-Dw2

T-cell lines specific for purified tuberculin (PPD), rubella, and herpes simplex virus (HSV) antigens were established from two Dw1/w2 heterozygous subjects. Fresh peripheral blood monocytes from healthy individuals with shared and non-shared D-antigens were used as presenting cells and the T-cell lines as responders in lymphocyte blast transformation assays with specific antigens. An HLA-restricted reaction was seen with all the antigens, although the PPD- and HSV-specific cell lines reacted stronger than rubella-specific lines when the specific antigens were presented by monocytes not sharing the D-antigens. A significantly lower response was seen when rubella antigen was presented by Dw2 positive monocytes as compared to response promoted by Dw1 positive monocytes (p less than 0.0001, Mann-Whitney U-test), whereas no such difference was seen in responses to PPD or herpes simplex antigen.

Immune functions in healthy blood donors with HLA-DW2 and -DW3 antigens

We compared healthy blood donors with and without HLA-Dw2 and -Dw3 in immunity assays, the results of which have been found to be abnormal in multiple sclerosis or autoimmune diseases. Tests included lymphocyte blast transformation responses to rubella, mumps and purified tuberculin (PPD), in vitro production of IgG and interferons, natural killer (NK) cell function and measurement of serum antibodies to measles, rubella, mumps and herpes simplex viruses. HLA-Dw2-positive subjects had a lower lymphocyte blast transformation response to rubella virus antigen and a lower NK cell function compared with HLA-Dw2-negative subjects. The presence of HLA-Dw3 was associated with an increased spontaneous and mumps virus-induced immunoglobulin production. No significant differences were found in other assays. These results support the existence of HLA-Dw2- and Dw3-associated deviation of immune responsiveness, which may contribute to the susceptibility of multiple sclerosis or other autoimmune type diseases.

HLA and multiple sclerosis: population and families study

Association between HLA and multiple sclerosis (MS) was investigated at the population level on 100 MS patients genotyped for HLA-A, B, C, DR and Bf, Glo, and on 155 patients phenotyped for the same HLA antigens. Association between MS and DR2 was clearly confirmed, although its strength is rather weak. No other genetic marker could be related to the disease, no haplotype nor any allelic combination could be recognized as MS specific, and antigen genotype frequencies among the diseased could not ascertain the mode of inheritance, although dominance is very likely. Computer analysis between HLA, Bf, Glo and age of the patient, sex, age of onset and evolution of MS, impairment indexes, titres of anti-DNA and anti-measles antibodies in CSF did not show any interaction. Twenty sib pairs and two trios of MS were also studied; they showed no significant distortion with the random distribution of haplotypes. DR2 gene frequency, however, was significantly higher in sib pairs showing one or two haplotypes than in HLA different affected siblings. Three crossing-overs were identified which suggest where the HLA-linked MS susceptibility (MSS) gene could be located within the HLA segment, while other epistatic MSS genes or environmental factors are likely to be important.

Influence of prostaglandin E2 and indomethacin on interferon-gamma production by cultured peripheral blood leukocytes of multiple sclerosis patients and healthy donors

The addition of indomethacin to concanavalin A (Con A)-induced cultures of human peripheral blood leukocytes (PBL) caused an increase in interferon response, regardless of whether the PBLs were derived from multiple sclerosis (MS) patients or from control donors. Specifically the response rates increased from 71 to 100% in controls and from 24 to 53% in MS patient-derived cultures. The amounts of interferon produced also increased in both groups by 0.8 log U/ml. However, interferon yields of nonresponsive cultures becoming interferon-producing only after indomethacin treatment remained relatively low. In control cultures, maximal increases of interferon production were obtained with doses of 0.05 to 0.1 microgram/ml indomethacin; for MS patients higher doses were needed--0.1 to 0.5 microgram/ml. Conversely, a relatively low dose (0.05 microgram/ml) of exogenous prostaglandin E2 (PGE2) was able to inhibit interferon production completely in MS patient-derived cultures, whereas in control cultures higher doses were needed (0.1 to 1.0 microgram/ml). Analysis of endogenous PGE2 levels in the PBL cultures revealed that PGE2 production was similar in nonresponder MS cultures and responder control cultures but that MS leukocytes were more sensitive to the inhibitory effect of PGE2 on interferon production. We conclude that in a minor percentage of MS patient-derived PBL cultures, the deficiency in interferon-gamma (IFN-gamma) production can be (partially) overcome by treatment of the cells with indomethacin. However, in the major part of nonresponder MS cultures, indomethacin has no effect, indicating that the PG system is not the major cause for the defective interferon response in MS.

Abnormalities of serum and plasma components in patients with multiple sclerosis

Qualitative and quantitative abnormalities in protein and non-protein components of serum and plasma in patients with multiple sclerosis have been the subjects of numerous reports. In this review many of the more recent observations are documented and evaluated. It is concluded that at present the welter of information that has been gathered does not contribute in any major, coherent way to our understanding of the etiology or pathogenesis of the disorder. Several of the abnormalities that have been observed may be future candidates for biochemical markers for multiple sclerosis; at present none is sufficiently reliable, distinctive or easily performed to warrant the status of a useful diagnostic or prognostic test.

A review of the etiology of multiple sclerosis

The geographic distribution of multiple sclerosis and the influence of migration on the risk of contracting it point to an environmental factor as cause of the disease. This environmental factor might be a virus which might produce the demyelination process through an autoimmune reaction against components of the central nervous system. The other possible cause of multiple sclerosis is a genetic susceptibility, inferred from the higher risk for the disease found among relatives of patients with multiple sclerosis and on the association between the disease and some histocompatibility antigens of the HLA system. Both theories seem to be correct, with the environmental factors(s) causing multiple sclerosis only in the presence of a genetic susceptibility.

Studies of interferon production and natural killing by lymphocytes from multiple sclerosis patients

Peripheral blood lymphocytes from patients with multiple sclerosis (MS) have been shown by numerous investigators to function abnormally in a variety of immunological tests in vitro. In this article, data concerning defective natural killer (NK) cell function and interferon production by MS patients' lymphocytes have been reviewed. Production of IFN-alpha and IFN-gamma by appropriately stimulated lymphocytes has been shown to be significantly reduced in many patients with acute remitting or chronic progressive disease. Furthermore, a significant proportion of these patients has been found to exhibit reduced levels of endogenous and augmented NK cell activity. A likely explanation for these phenomena is that altered traffic occurring as a consequence of disease has led to a relative loss of NK and IFN-producing cells from the peripheral circulation. Flow cytometric data obtained using monoclonal antibodies that selectively label these effector populations were presented. Possible explanations for the observed defects and their significance relative to our understanding of the etiopathogenesis of MS were discussed.

Cytotoxic activity of peripheral blood and cerebrospinal fluid lymphocytes from patients with multiple sclerosis and other neurological diseases: analysis at the single cell level of the relationship of cytotoxic effectors and interferon-producing cells

The production of interferon (IFN alpha) in relationship to NK and ADCC activity of peripheral blood and cerebrospinal lymphocytes was examined at the single cell level in patients with multiple sclerosis (MS) and other neurological diseases (OND) compared with age- and sex-matched controls. IFN-producing cells were assessed by indirect immunofluorescent scoring of cytoplasmic IFN+ cells. Peak production of cytoplasmic IFN alpha in nylon wool-passed ( NWP ) cells occurred between 5 and 17 hr in vitro under the inductive stimulus of MOLT 4, K562, or antibody-coated Chang liver cells. The proportion of K562- and MOLT 4-induced IFN alpha-positive cells in the total lymphocyte and target-binding cell (TBC) population was significantly lower in MS NWP -peripheral blood lymphocytes (PBL) than in OND and normal controls; this was in direct relationship to a decreased percentage of NK cells in MS PBL. In contrast MS cells responded the same as controls (total IFN+ cells) or higher than controls (IFN+-TBC) after IFN alpha induction by antibody-coated Chang, the ADCC target, in parallel with elevated ADCC activity by MS PBL. MS CSF contained a higher proportion of total IFN+ cells but a similar proportion of IFN+-TBC as their homologous NWP PBL population. In OND CSF, both the percentage of total IFN+ and the percentage of IFN+-TBC were higher than in OND blood and higher than their respective MS CSF populations. The relationship of IFN-producing cells in the central nervous system (CNS) to putative cytotoxic cells is discussed.

Leukocyte surface antigens in patients with multiple sclerosis

Lymphocyte phenotypes have been measured in 20 normal females, 19 normal males, 3 females with acute exacerbations of MS and 21 females and 17 males with chronic progressive MS. Using a FACS IV, lymphocytes were gated by light scattering properties, and fluorescence was analyzed using a log amplifier. No abnormalities were found in the 3 females with acute exacerbations. In male patients the percentage of OKT8 was significantly reduced, the percentage of OKT4 was significantly increased, and the ratio of OKT4/T8 was increased. In females with chronic progressive disease the percentage of OKT8 was not statistically altered, but the percentage of OKT4 and the OKT4/T8 ratio were elevated. Interpretation of these findings requires more extensive study in control populations.

Natural killer cell activity in patients with multiple sclerosis given alpha interferon

The purpose of this study was to examine the function and regulation of natural killer cells in vitro and in vivo in patients with multiple sclerosis. Of 12 patients who received 5 X 10(6) international units of human alpha interferon, 9 demonstrated an increase in natural killer cell activity within 48 hours as defined by the lysis of 51Cr-labeled K-562 cells. The activity was normal before treatment, unlike that of tumor-bearing patients, and reached baseline levels within one week despite continuous interferon administration over the next six months. The same patients given a placebo preparation failed to show this enhanced natural killer cell activity. We also studied K-562 killing in 36 other patients and age- and sex-matched control subjects and were unable to demonstrate any differences between the two groups or any correlation of natural killer cell function with disease activity. The in vitro augmentation of natural killer cell activity by purified measles virions, which is associated with the release of interferon, and by the isolated glycoproteins of measles virus, which activates natural killer cells without the extracellular release of interferon, was similar in both patients and control subjects. Further, the proportion of cells defined by the monoclonal antibody HNK-1, which defines both natural killer cells and a small subset of cytotoxic T lymphocytes, was normal. In patients with multiple sclerosis, the normality of natural killer cell function, as defined by these several interrelated assays, speaks against a defect in this nonspecific antiviral defense mechanism in the pathogenesis of the disease.

Interferon production and natural killer (NK) activity in leukocyte cultures from multiple sclerosis patients

Peripheral blood leukocyte (PBL) cultures from only 37% of MS patients produced detectable HuIFN-gamma in response to ConA as opposed to 85% of the cultures derived from normal blood donors. However, the yields in patient-derived cultures that were responsive, were not lower than those in cultures from controls. Production of HuIFN-alpha after stimulation with Sendai virus was not aberrant in cells taken from MS patients. The difference in HuIFN-gamma response rate between MS and normal donor-derived cells was more pronounced when DR2+ carriers were compared amongst each other than when DR2-k carriers were compared. Among the MS patients, the failure of PBLs to produce HuIFN-gamma in response to ConA was not correlated with age, sex, disease duration and type of disease. However, positive correlations were found with current disability indices and past disease progression rates. Unstimulated NK-activities of MS patient-derived PBLs were not different from those of normal donor-derived cells. the degree of augmentation of the activity by stimulation with ConA and interferon-alpha was also normal. Within the MS patients group, but not in the control group, there was a trend for DR2+ carriers to have lower spontaneous and stimulated NK-activities than DR2- individuals.

Lymphocyte blast transformation responses to mitogens and specific antigens in different clinical phases of multiple sclerosis: a follow-up study

28 MS patients were studied at least 5 times for lymphocyte blast transformation responses to several mitogens (PHA, Con, PWM) and specific antigens (PPD, herpes simplex, measles, mumps, rubella), the mean duration of the follow-up being 15.3 months. Comparison of responses during remissions, exacerbations and ACTH treatment revealed no straight-forward association between the strength of response and clinical disease activity. Mitogen responses did not differ among various disease phases, but the PPD response was significantly lower during exacerbations than during remissions and still lower during ACTH treatment (P less than 0.05, Wilcoxon paired test). In responses to viral antigens, there was the same trend as in the PPD response. However, there were great individual differences in the behaviour of all antigen and mitogen induced lymphocyte responses. As a group, MS patients also showed more changes in their PHA mitogen responses during the follow-up than 8 control subjects followed similarly (P less than 0.005, F-test). The variation coefficient of the PHA response was also correlated with the maximal difference in the Fog neurologic deficit scale during the follow-up time (r = 0.460, P less than 0.05). However, patients with greatest clinical changes most often also received ACTH treatment, which may affect the results. The follow-up results of individual patients revealed that some had quite regular patterns of decreasing responses during disease relapses, whereas others had more irregular wide fluctuations of responses.

An interferon assay based on yield reduction of vesicular stomatitis virus antigen measured by enzyme immunoassay

A modification of yield reduction assay for interferon was developed. The standard micromethod of inhibition of cytopathogenic effect (CPE) of vesicular stomatitis virus (VSV) was first applied and the amount of virus antigen released to the supernatant was then measured by a competitive enzyme immunoassay technique. This assay was four times more sensitive than the CPE inhibition method and was able to detect 0.50-0.25 international units/ml of human interferon-alpha and was also applicable to interferon-gamma determinations. It is a suitable method when small volumes of samples containing low levels of interferon are tested.

Defective production of interferon-alpha associated with HLA-DW2 antigen in stable multiple sclerosis

Interferon (IFN) production by peripheral blood mononuclear cells after induction with one purified and three crude viral antigens was studied in 29 patients with stable multiple sclerosis (MS) and 29 healthy controls. Antiviral substance produced was characterized as interferon-alpha. MS patients produced significantly less IFN-alpha after induction with mumps and purified measles virus antigens and the same tendency was seen after induction with rubella virus antigen. However, when herpes simplex virus antigen was used as the stimulating agent, no difference was seen between MS patients and controls. The decreased ability to produce IFN-alpha was associated with the histocompatibility antigen Dw2. Control subjects positive for Dw2 also produced less IFN-alpha than Dw2-negative controls. In conclusion, we suggest that the observed impaired interferon-alpha production in MS is at least partially due to a high prevalence of Dw2 antigen in this disease.